Design of soft magnetic materials

Abstract

We present a strategy for the design of ferromagnetic materials with exceptionally low magnetic hysteresis, quantified by coercivity. In this strategy, we use a micromagnetic algorithm that we have developed in previous research and which has been validated by its success in solving the “Permalloy Problem”—the well-known difficulty of predicting the composition 78.5% Ni of the lowest coercivity in the Fe–Ni system—and by the insight it provides into the “Coercivity Paradox” of W. F. Brown. Unexpectedly, the design strategy predicts that cubic materials with large saturation magnetization ms and large magnetocrystalline anisotropy constant κ1 will have low coercivity on the order of that of Permalloy, as long as the magnetostriction constants λ100, λ111 are tuned to special values. The explicit prediction for a cubic material with low coercivity is the dimensionless number $$({c}_{11}-{c}_{12}){\lambda }_{100}^{2}/(2{\kappa }_{1})=81$$ ( c 11 − c 12 ) λ 100 2 / ( 2 κ 1 ) = 81 for 〈100〉 easy axes. The results would seem to have broad potential application, especially to magnetic materials of interest in energy research.

A Magnetoelastic Twist on Magnetic Noise: The Connection with Intrinsic Nonlinearities

“…[1][2][3] On the other hand, it has been shown that nonzero magnetostriction can be beneficial for achieving low values of magnetic hysteresis in ferromagnetic films. [4,5] Ferromagnetic thin-film-based devices, especially magnetic field sensors, have numerous applications in the modern world, ranging from navigation systems to medical diagnostics and data storage applications. [6] These include magnetoresistive (XMR) sensors based on the anisotropic (AMR), [7][8][9] the giant (GMR), [10][11][12][13][14] and the tunnel magnetoresistive (TMR) [15][16][17] effects, mostly comprising magnetostrictive layer compositions for optimization of XMR effect strength or feasibility of fabrication.…”

Tailoring magnetic hysteresis of Fe-Ni permalloy by additive manufacturing: Multiphysics-multiscale simulations of process-property relationships

“…Recently, it has been shown that soft magnetic properties can be designed by controlling magneto-elastic coupling [21,22,23]. Along these lines, the residual stress caused by AM and the underlying phase transitions could be key for tuning the coercivity in an AM-processed Fe-Ni permalloy.…”

“…Based on a vast number of calculations, the dimensionless constant (C 11 − C 12 )λ 2 100 /2K u ≈ 81 was proposed as a condition for low coercivity along the 100 crystalline direction for cubic materials (incl. Fe-Ni permalloy) [23]. Here, C 11 and C 12 are the components of the stiffness tensor, λ 100 is the magnetostrictive constant, and K u is the magneto-crystalline constant.…”

Understanding magnetocrystalline anisotropy based on orbital and quadrupole moments

“…arXiv:2209.04070v1 [cond-mat.mtrl-sci] 9 Sep 2022 Contrary to this, some studies suggest the importance of in-plane MCA of magnetic materials for applications such as a magnetic under-layer of a perpendicular recording medium [4] and a spin torque oscillator for microwave-assisted magnetic recording (MAMR) [5,6]. Furthermore, the development of soft magnets requires extremely small MCA under distortion to eliminate losses caused by magnetic hysteresis and circulating loops of current [7]. Hence, understanding MCA is necessary for the development of novel magnetic materials.…”